Too much time online can expand your waistline, a new study shows
If you really want to win the weight-loss battle, learn to strike a balance — not just on your plate, but also in how you spend your free time. A new study published in the Journal of Medical Internet Research finds that people who spend more time in front of computers have a higher obesity risk, even if they think they get enough exercise during the week.
The researchers surveyed 2,650 Australian adults and asked them questions about their levels of physical activity, Internet and computer use during leisure time, and other sedentary activities, such as reading, talking on the phone, playing video games, or watching television. Internet use and physical activity were divided into three categories: none, low (less than three hours per week), and high (more than three hours); sedentary activities were divided into low (less than 2.5 hours), medium (2.5 to 5 hours per week), and high (more than five hours).

People with the highest levels of computer use were 1.5 times more likely to be overweight and 2.5 times more likely to be obese than people who didn't use a computer at all. Those people were also more likely to report lower levels of physical activity, and were 2.5 times more likely to engage in more than five hours a day of other sedentary activities. But interestingly, adults who spent a lot of time at the computer and still had high levels of physical activity were 1.86 times more likely to be overweight or obese than people who spent no time in front of the computer.
This study found only an association between weight and computer use. "Is it that you become overweight because you use the Internet a lot, or is it that overweight people simply use the Internet more?" It's hard to say. But one likely explanation, she adds, is that "people who use the Internet a lot also engage more in other sedentary behaviors, and that is likely the main cause of their being more likely to be overweight."
Those additional sedentary activities may be throwing off your perceptions of your own exercise habits, too. "If I go running three times a week for one hour, but watch TV the rest of my time, I will still be very sedentary. "I might be fit, which is definitely a good thing, but it might also be that I'm still not spending enough energy on a daily basis." Formal exercise can only partially compensate for all the time you spend sitting around, she adds. Including regular activity as part of your everyday routine is equally important.
It's all about striking a balance between sitting down and moving around, Vandelanotte says. Here are a few ways to keep computer time from undermining a healthy lifestyle: How to tackle it?
Set a timer: For your computer use, for your television watching — for anything that keeps you on the couch. The less time you spend not moving, the more likely you are to get a healthy, and perhaps waist-shrinking, dose of physical activity. Set time limits that will allow you to enjoy the Web sites or TV shows you like, without leaving time for unneeded browsing or channel surfing that just keeps you off your feet. Be an active viewer: You might not be able to move around while sitting at the computer, but when you're watching TV, spend at least some of the time doing something physical, whether it's exercising or cleaning.
Aim for 250: The American College of Sports Medicine recommends that to prevent weight gain, people spend 150 minutes per week exercising and 250 minutes per week if they want to lose weight. It's a lot easier to get those 250 minutes of exercise if you cut back on the time you spend in front of the computer.